1. Field of the Invention
The invention relates to a strand coating device, and more particularly to a head assembly for pressurized coating of optical fibers.
2. Description of the Prior Art
The coating of elongated strands of fiber material, such as glass fibers used in fiber optics, has been accomplished by a method referred to generally as the "open cup" method, which is illustrated and described in U.S. Pat. No. 4,419,958, issued Dec. 13, 1983 to Giacomo Roba. Utilizing such method, fibers of silica glass are passed in a downward direction through a mass of liquid resin contained in a reservoir which terminates in a converging outlet duct. The reservoir and outlet duct are referred to by Roba as the "nozzle". After the fiber emerges from the duct, its resin coating is allowed to set by drying or curing. To facilitate the insertion of the fiber under traction into the nozzle, the nozzle body of Roba is split into two parts with complementary cavities defining the passage.
In U.S. Pat. No. 4,510,884, issued Apr. 16, 1985 to Nathan B. Rosebrooks, there is shown and described a device for coating an optical fiber in which the coating material is supplied to chamber under pressure and the fiber strand is drawn downwardly through the chamber. Using the pressurized chamber, the Rosebrooks device facilitates the movement of the fiber through the device at a substantially higher rate of speed than is the case with a device of the Roba type.